Community stability and selective extinction during the Permian-Triassic mass extinction

Area of Science:

• Paleontology
• Ecology
• Earth Science

Background:

• The fossil record reveals periods of extreme biodiversity loss, known as mass extinctions.
• The Permian-Triassic extinction event represents Earth's most severe known biodiversity crisis.

Purpose of the Study:

• To investigate the stability of terrestrial paleocommunities in South Africa during the Permian-Triassic mass extinction.
• To determine the factors influencing community stability during this severe extinction event.

Main Methods:

• Analysis of the fossil record from South Africa.
• Comparison of paleocommunity stability with model communities exhibiting different organizational structures.
• Assessment of the role of functional diversity and guild interactions versus species richness.

Main Results:

• Terrestrial paleocommunity stability was critically dependent on functional diversity and guild interaction patterns, not species richness.
• Paleocommunities showed less transient instability and higher probabilities of local stability compared to model communities.
• Evolved functional patterns supported more stable communities than hypothetical alternatives.

Conclusions:

• Functional diversity and established ecological interactions are key to ecosystem resilience during mass extinctions.
• Species richness alone is not a reliable indicator of community stability in the face of extreme environmental change.
• The historical development of functional traits within an ecosystem enhances its long-term stability.